// RuleHash calculates a hash for the relevant bits of this rule that affect its output.
// Optionally it can include parts of the rule that affect runtime (most obviously test-time).
// Note that we have to hash on the declared fields, we obviously can't hash pointers etc.
// incrementality_test will warn if new fields are added to the struct but not here.
func RuleHash(target *core.BuildTarget, runtime, postBuild bool) []byte {
if runtime || (postBuild && target.PostBuildFunction != 0) {
return ruleHash(target, runtime)
}
// Non-post-build hashes get stored on the target itself.
if len(target.RuleHash) != 0 {
return target.RuleHash
}
target.RuleHash = ruleHash(target, false) // This is never a runtime hash.
return target.RuleHash
}